json_parse returned success when input ended while the tokener was

still waiting for more data, and also after read() failures.

Finalize the tokener at EOF with the terminating NUL so valid scalar
values can complete, while rejecting genuinely truncated input.

Also propagate read errors to the caller and add CLI regression tests.

apps/json_parse.c

@@ -143,6 +143,27 @@ static int parseit(int fd, int (*callback)(struct json_object *))
 		json_tokener_free(tok);
 		return 1;
 	}
+	if (json_tokener_get_error(tok) == json_tokener_continue)
+	{
+		obj = json_tokener_parse_ex(tok, "", 1);
+		if (obj != NULL)
+		{
+			int cb_ret = callback(obj);
+			json_object_put(obj);
+			if (cb_ret != 0)
+			{
+				json_tokener_free(tok);
+				return 1;
+			}
+		}
+		if (json_tokener_get_error(tok) != json_tokener_success)
+		{
+			fprintf(stderr, "Failed at offset %lu: unexpected end of data\n",
+			        (unsigned long)total_read);
+			json_tokener_free(tok);
+			return 1;
+		}
+	}
 
 	json_tokener_free(tok);
 	return 0;